JP4519927B2 - Rotation angle detector - Google Patents

Description

  The present invention relates to a rotation angle detection device suitable for detecting the rotation angle of a detection object such as a steering shaft of a vehicle, for example.

  This type of rotation angle detection device is suitable for use in detecting the rotation angle of a steering shaft that is rotated by a driver's steering operation as an absolute angle, for example, with regard to vehicle attitude control technology. In general, the rotation angle is detected by calculating the absolute angle from the phase difference of rotation generated between a plurality of driven gears meshing with the main driving gear while rotating the main driving gear integrally with the rotation of the steering shaft. The calculation method is adopted. When detecting the rotation angle, the driven gear is particularly required to rotate with a low torque and without a load. Therefore, a certain clearance is required between the driven gear and its bearing portion. However, when such a clearance is provided, there are problems that the driven gear rattles in the axial direction when the vehicle is traveling, and the detection accuracy is lowered, or abnormal noise is generated due to vibration.

  For this reason, there is conventionally known a prior art in which the driven gear is elastically pressed in the axial direction to suppress the occurrence of rattling and vibration noise during traveling (see, for example, Patent Document 1). In this prior art, a driven gear having a magnet at the center is accommodated in a case member, and a bearing recess is formed on the inner surface of the case member so that the driven gear is rotatably supported at one end thereof. is there. In the case member, a circuit board is disposed at a position opposite to the magnet on the other end side of the driven gear, and a magnetic change detecting element for detecting a change in the magnetic field is mounted on the circuit board. In particular, in the prior art, a spring member is installed between the case member and the driven gear on one end side of the driven gear, and the driven gear is pressed against the circuit board by its elastic force.

According to the above prior art, the driven gear can be rotated with low torque while suppressing rattling and vibration of the driven gear even if there is a clearance between the bearing recess and the circuit board and the driven gear. It is thought that you can.
Japanese Patent Laying-Open No. 2004-279265 (page 4-5, FIGS. 1 and 4)

  However, in the prior art, the mechanical parts such as the main driving gear and the driven gear and the circuit board are arranged in the same space in the case member, so that the solder balls and residual flux are separated from the circuit board due to vibration during running and long-term use. Or foreign matter such as broken pieces or fine powder is generated from the fractured surface of the circuit board, and these foreign matters are brought into contact with the main gear and the driven gear and the sliding parts between each gear and the circuit board. There arises a problem that the rotation torque of these gears increases and it becomes difficult to rotate smoothly, or the teeth of the gears are damaged and accurate rotation angle cannot be detected.

  The present invention has been made in view of the actual state of the prior art, and its purpose is to rotate the main driving gear and the driven gear smoothly with low torque, and to prevent damage to the teeth of each gear. An object of the present invention is to provide an angle detection device.

In order to solve the above problems, the present invention employs the following solutions.
That is, the rotation angle detection device of the present invention includes a main driving gear that is rotated directly or indirectly connected to a detection object that rotates about a predetermined axis, a driven gear that meshes with the main driving gear, and a driven gear. It has a magnet provided in the central part and a first insertion hole formed so that a detection object can be inserted, and the first insertion hole rotatably supports the main gear and rotatably supports the driven gear. A holder member having a support portion and having an opening facing the magnet formed in the support portion and a second insertion hole formed so that a detection object can be inserted are assembled to one side of the holder member. A first cover member that rotatably holds the driven gear and the driven gear between the holder member, forms a first space for accommodating the driven gear, and allows a portion of the driven gear to face the first space; The magnet turns opposite the magnet through the opening. A magnetic detection element for detecting a change in magnetic field due to rolling, a circuit board on which the magnetic detection element is mounted, and a third insertion hole formed so that a detection object can be inserted, and is attached to the other side of the holder member And a second cover member that forms a second space for accommodating the circuit board between the holder member and the opening is closed by the circuit board.

  According to the rotation angle detection device of the present invention, the second space in which the circuit board on which the magnetic detection element is mounted is isolated from the first space in which the main driving gear and the driven gear are stored. Even if the solder balls and residual flux are separated from the circuit board depending on the period of use, or broken pieces or fine powder etc. are generated from the fracture surface of the circuit board, these foreign matters are in contact with the main gear and the driven gear. Since it does not adhere to the sliding part of each gear and holder, the main driving gear and the driven gear can be rotated smoothly with low torque, and damage to the teeth of each gear can be prevented. A highly reliable rotation angle detection device can be provided.

  In the rotation angle detection device of the present invention, the holder member, the first cover member, the main driving gear, and the driven gear are molded from a synthetic resin material, and a metal plate is interposed between the first cover member and the main driving gear and the driven gear. It is preferable that the sheet-like member processed from the above is interposed.

  In the above aspect, the upper and lower sides of the main driving gear and the driven gear are in contact with the synthetic resin holder member and are rotated on the other side in contact with the metal sheet-like member. Can rotate with a small frictional resistance compared to the case of contacting the holder member and the first cover member made of synthetic resin. Therefore, rattling and vibration of the driven gear can be prevented, and the driven gear can be smoothly rotated.

  Further, the rotation angle detection device of the present invention may be an embodiment in which the holder member, the main driving gear, and the driven gear are formed from a synthetic resin material, and at least the first cover member is processed from a metal plate. In this case, the main driving gear and the driven gear can be rotated with a smaller frictional resistance. Therefore, these gears can be rotated more smoothly. Moreover, since the thickness of the first cover member can be reduced, the rotation angle detection device can be made compact.

  The rotation angle detection device of the present invention has a configuration in which the main driving gear and the driven gear are not disposed in the space in which the circuit board on which the magnetic detection element is mounted is accommodated, so that solder balls and residual flux are separated from the circuit board, Even if broken pieces, fine powder, etc. fall off or generate from the fracture surface of the circuit board, these foreign matters should adhere to the meshing part of the main and driven gears, the sliding part of each gear and the holder, etc. Therefore, the main driving gear and the driven gear can be smoothly rotated with a low torque, and damage to the teeth of each gear can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 is a perspective view of a rotation angle detection device 10 according to an embodiment, FIG. 2 is an overall exploded perspective view of the rotation angle detection device of FIG. 1, and FIG. 3 is a diagram illustrating a holder member, a main driving gear, and a driven gear in FIG. FIG. 4 is a perspective view showing the meshing state of the main driving gear and the driven gear in FIG. 3, FIG. 5 is a front view of the rotation angle detecting device of FIG. 1, and FIG. It is sectional drawing along a VI-VI line. The rotation angle detection device 10 is used, for example, to detect the rotation angle of a steering shaft of a vehicle that is a detection target as an absolute angle.

  In the rotation angle detection device 10 shown in FIG. 1, a holder member 30, a first cover member (case) 40, and a second cover member (cover) 20 are integrated by snap coupling. A rotary connector (not shown) is laminated on the outer surface side. The rotary connector is for electrically connecting the handle side and the vehicle body side, and is formed between a movable housing connected to the handle and a fixed side housing fixed to a stator member such as a steering device. A flat cable is stored and wound in the storage space. Since the main driving gear 12 of the rotation angle detecting device 10 has a projection 15 formed on the main driving gear 12 engaged with a recess formed on the movable housing, the steering rotates around the axis CL in accordance with the steering operation. Rotates integrally with the shaft. Further, the rotation angle detection device 10 and the fixed housing of the rotation connector are screwed together with a screw (not shown) inserted through the screw insertion hole 10a at the peripheral portion of the rotation angle detection device 10. Further, the cam rotor 50 to be described later is attached to the rotation angle detecting device 10 by snapping the claw portion 12g of the main driving gear 12 to the engaging groove 50a.

  The main drive gear 12, which is a molded product made of synthetic resin, has an insertion hole 12 a through which a steering shaft is inserted, and a small diameter portion 12 e is continuous with a large diameter portion 12 d in which two stages of gears 12 b and 12 c having different numbers of teeth are formed. (FIG. 4 etc.). When the small-diameter portion 12e is inserted into the first insertion hole 30a of the holder 30, the main driving gear 12 has the lower surface of the large-diameter portion 12d on the surface around the second insertion hole 30a of the holder 30, as shown in FIG. It abuts and is supported rotatably with respect to the holder 30. The large-diameter portion 12d is formed with a ring-shaped first ring portion 12f protruding toward the inner surface of the case 40, and the end surface of the first ring portion 12f is provided on the inner surface of the case 40. Abuts against the shaped member 80.

  As shown in FIG. 1, the main driving gear 12 and the cam rotor 50 are integrated by snap-joining the claw portion 12 g of the inner wall forming the insertion hole 12 a of the main driving gear 12 and the engaging groove 50 a of the cam rotor 50. The main gear 12 has a projection 15 projecting outward from the large diameter portion 12d along the axis CL, and the projection 15 is formed in a concave portion of the movable housing of the rotary connector laminated on the outer surface side of the case 40. Engaged. Accordingly, the main driving gear 12 is connected to the movable housing, and the movable housing is connected to the steering shaft via the handle. Therefore, the main driving gear 12 is indirectly connected to the steering shaft and rotates in accordance with the operation of the handle. Become.

  The driven gears 13 and 14, which are molded products made of synthetic resin, have holding portions 13b and 14b in which gears 13a and 14a having the same number of teeth are formed, and are engaged with the gears 12b and 12c of the main driving gear 12 to have different rotational speeds. To rotate each. The magnet 16 is accommodated in the accommodating portions 13c and 14c formed at the center of the holding portions 13b and 14b. When the holding portions 13b and 14b of the driven gears 13 and 14 are inserted into the first support portions 30e and 30f (recessed portions) of the holder 30, the driven gears 13 and 14 are respectively rotatable to the holder 30 as shown in FIG. The magnet 16 is opposed to each opening 30g formed in the first support portions 30e and 30f. Further, as shown in FIG. 6, the holding portions 13b and 14b are formed in an annular shape so that the second ring portions 13d and 14d protrude toward the inner surface of the case 40, and the second ring portions 13d and 14d The end surface is in contact with the sheet-like member 80 provided on the inner surface of the case 30.

  The dimensions of the holding portions 13b and 14b of the driven gears 13 and 14 and the second ring portions 13d and 14d in the direction along the axis CL are such that the gears 13a and 14a and the gear portions 12a and 12b of the main driving gear 12 mesh with each other. It is set appropriately. As shown in FIG. 3, projecting portions 13e and 14e are formed at the ends of the storage portions 13c and 14c on the holder 20 side, respectively. The protruding portions 13e and 14e are for securely fixing the magnets 16 in the storage portions 13c and 14c, and are pressed and deformed by the heating body in a state where the magnets 16 are stored in the storage portions 13c and 14c.

  The magnet 16 is a quadrangular ring body, and one of a pair of opposing sides is magnetized with an N pole and the other is magnetized with an S pole. The magnet 16 is mounted in the storage portions 13c and 14c of the two driven gears 13 and 14. It is done. When the magnet 16 is housed and fixed in the housing portions 13c and 14c, the lines of magnetic force are generated in parallel along the surface of the magnet 16, so that a change in the magnetic field accompanying the rotation of the magnet 16 is accurately detected by the magnetic detection element 72. be able to.

  As shown in FIG. 3, the holder 30, which is a synthetic resin molded product, has a bottom plate portion 30 b formed with a first insertion hole 30 a through which the steering shaft is inserted, and is reversed along an axis CL from the outer edge portion of the bottom plate portion 30 b. Standing portions 30c and 30d that stand in the respective directions, and first support portions 30e and 30f that rotatably support the driven gears 13 and 14 are provided. The first support portions 30e and 30f have recesses into which the holding portions 13b and 14b of the driven gears 13 and 14 are rotatably inserted. Openings 30g and 30g facing the magnets 16 are formed on the inner bottom surfaces of the recesses. Is formed. As shown in FIG. 6, when the holding portions 13b and 14b of the driven gears 13 and 14 are inserted into the first support portions 30e and 30f, the driven gears 13 and 14 are rotatably supported by the holder 30 and each magnet. 16 opposes each opening 30g. The depth dimensions of the first support portions 30e and 30f are appropriately set according to the dimensions of the holding portions 13b and 14b of the driven gears 13 and 14. As shown in FIGS. 1 and 3, a plurality of hook portions 30 h and claw portions 30 i extending in the circumferential direction are formed on the outer surface of the holder 30, and the case 40 and the cover 20 are attached to the holder 30. The opening ends of the case 40 and the cover 20 are hooked by the hooking portion 30h, and the engagement hole 40d formed on the side surface of the case 40, and the engagement hole 20d formed on the side surface of the cover 20 and the claw portion 30i. Snap-joined. The holder 30 has a protruding portion 30j extending laterally.

  The case 40 is also a molded product made of synthetic resin, and is formed with a bottom plate portion 40b in which a second insertion hole 40a is inserted through the steering shaft, and an upright portion 40c that rises from the outer edge portion of the bottom plate portion 40b toward the holder 30. It forms a hollow recess that opens toward the holder 30. Therefore, when the case 40 is attached to the holder 30, a space S1 as a first space is formed between the case 40 and the holder 30, and the driven gears 13 and 14 are accommodated in the space S1. The main driving gear 12 and the driven gears 13 and 14 are rotatably held between the case 40 and the holder 30. As shown in FIG. 6, the space S <b> 1 is formed by being surrounded by the holder 30, the circuit board 70, the case 40, and the main driving gear 12. A part of the main driving gear 12, that is, the gears 12b and 12c formed on the large diameter portion 12d faces the space S1. An engagement hole 40d that is snap-coupled to the claw portion 30i of the holder 30 is formed on the outer surface of the standing portion 40c. The bottom plate portion 40b is formed with a positioning recess 40e for positioning and arranging a sheet-like member 80 described later. Further, the case 40 is formed with a projecting portion 40f having a shape corresponding to the projecting portion 30j of the holder 30 extending laterally.

  The magnetic detection element 72 uses a GMR (Giant Magneto-Resitive) sensor, and is mounted on the circuit board 70 so as to face the magnet 16 through the opening 30 g of the holder 30.

  As shown in FIG. 2, the circuit board 70 has a protruding portion 70a having a shape corresponding to the protruding portion 30j of the holder 20, and the protruding portion 70a has a plurality of connection terminals for connecting to an external connector. A connector 75 is provided. Further, the circuit board 70 is fixed to the holder 30 with screws 90 in a state of closing each opening 30g.

  The cover 20 is also a molded product made of synthetic resin, and includes a bottom plate portion 20b formed with a third insertion hole 20a through which the steering shaft is inserted, and an upright portion 20c rising from the outer edge portion of the bottom plate portion 20b toward the holder 30. It is formed and forms a hollow recess that opens toward the holder 20. Therefore, when the cover 20 is attached to the holder 20, a space S <b> 2 in which the circuit board 70 is accommodated is formed between the cover 20 holder 30. An engagement hole 20d that is snap-coupled to the claw portion 30c of the holder 30 is formed on the outer surface of the standing portion 20c. Further, the cover 20 has a protruding portion 20e protruding sideways, and the protruding portion 20e has a connector lead-out portion 20f for providing a connector 90.

  As shown in FIG. 1, a plurality of pin insertion holes 20 g are formed in the bottom plate 20 b of the cover 20. In these pin insertion holes 20g, contact probes are inserted when electrical characteristics are inspected or software is written in a built-in device after the rotation angle detector 10 is assembled. Yes. In addition, after completion | finish of a test | inspection etc., the pin insertion hole 20g is block | closed by sticking the label 25 like illustration.

  The sheet-like member 80 is formed by processing a metal plate made of stainless steel plate or the like into a predetermined shape, has an opening 80a through which the steering shaft can be inserted, and can position the ends of the second ring portions 13d and 14d. It has a convex ring or the like (not shown).

  As shown in FIG. 1, the cam rotor 50 includes a cylindrical body 50 b that can be inserted into the insertion hole 12 a of the main driving gear 12, and a flange part 50 c that extends radially outward from the end of the cylindrical body 50 b. Have. A plurality of engaging grooves 50a are formed in the cylindrical body 50b. When the cylindrical body 50b is inserted into the first insertion hole 12a of the main driving gear 12, the cam rotor 50 is snap-coupled to the engaging groove 50a and the claw portion 12g, so that the cam rotor 50 can rotate integrally with the main driving gear 12. Become. Further, a cancel projection 50d is provided on the flange portion 50c of the cam rotor 50 so as to project outward along the axis CL. The cancel protrusion 50d is for returning the operation lever of the turn signal switch (not shown) to the neutral (OFF) position when either the left or right operation (ON) is performed.

  The rotation angle detection device 10 configured as described above is attached so that the circuit board 70 on which the magnetic detection element 72 is mounted closes each opening 30g of the holder 30. Since the space S1 in which the gear 12 and the driven gears 13 and 14 are accommodated is isolated from each other, the solder balls and the residual flux are separated from the circuit board 70 by long-term use, or the fracture pieces are broken from the fracture surface of the circuit board 70.・ Even if fine powder or the like is dropped or generated, these foreign matters may adhere to or interpose on the meshing portion of the main driving gear 12 and the driven gears 13, 14, the sliding portion of each gear and the holder 30, etc. Absent. Therefore, the main driving gear 12 and the driven gears 13 and 14 can be smoothly rotated with a low torque, and the gear teeth can be prevented from being damaged, so that the reliability can be improved.

  The case 40, the holder 30, the main driving gear 12 and the driven gears 13 and 14 are molded products made of synthetic resin, and are processed from a metal plate between the case 40 and the main driving gear 12 and the driven gears 13 and 14. Since the sheet-like member 80 is interposed, each of these gears can rotate with a small frictional resistance as compared with a configuration in which both end faces of each gear are in contact with the synthetic resin member. Therefore, rattling and vibration of the driven gears 13 and 14 can be prevented, and the driven gears 13 and 14 can be smoothly rotated. Further, the rotation angle detection device of the present invention may be an embodiment in which at least the case 40 is processed from a metal plate. In this case, since the main driving gear 12 and the driven gears 13 and 14 can be rotated with a smaller frictional resistance, these gears can be rotated more smoothly. Further, since the thickness of the case 40 can be reduced, the rotation angle detection device can be made compact. If the cover 20 is also constructed from a metal plate, the effect is even greater.

  Further, the holding portions 13 b and 14 b of the driven gears 13 and 14, which are the recessed portions of the holder 30, are inserted, and the small diameter portion 12 e of the main driving gear 12 is inserted into the first insertion hole 30 a of the holder 30. Thus, the driven gears 13 and 14 and the main driving gear 12 are rotatably supported by the holder 30, so that the main driving gear and the driven gear can be positioned with high accuracy by a simple mounting operation.

  In the present embodiment, the configuration in which the two driven gears 13 and 14 having the same number of teeth are meshed with the main driving gear 12 having the two-stage gears 12b and 12c having different numbers of teeth is shown. A plurality of driven gears with different numbers of teeth may be arranged in the main driving gear, or only one driven gear in one stage main driving gear may be arranged, and it can be applied to various gear configurations according to the purpose. Needless to say, you can.

  Further, in the present embodiment example, the configuration example in which the main driving gear 12 is indirectly connected to the steering shaft has been described. However, the main driving gear 12 of the rotation angle detection device 10 is directly connected to the steering shaft. Of course, the cam rotor 50 may not be attached to the rotation angle detection device 10.

It is a perspective view of the rotation angle detection apparatus of one Embodiment. It is the perspective view which decomposed | disassembled and showed the rotation angle detection apparatus to the main components. It is a disassembled perspective view which shows the assembly | attachment relationship of the mechanism component element with respect to a holder. It is a perspective view which expands and shows the meshing state of a main gear and a driven gear. It is a front view which shows the completion state of a rotation angle detection apparatus. FIG. 6 is a cross-sectional view showing the internal structure of the rotation angle detection device 10 in a completed state (cross-section VI-VI in FIG. 5).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotation angle detector 12 Main drive gear 14 Driven gear 16 Magnet 20 Cover 30 Holder 30g Opening 30e, 30f Support part 40 Case 70 Circuit board 72 Magnetic sensor 80 Sheet-like member

Claims (3)

A main gear that rotates in direct or indirect connection with a detection object that rotates about a predetermined axis;
A driven gear that meshes with the main gear and rotates;
A magnet provided in the center of the driven gear;
It has a first insertion hole formed so that the detection object can be inserted, and has a support portion that rotatably supports the main driving gear and rotatably supports the driven gear by the first insertion hole. A holder member in which an opening facing the magnet is formed in the support portion;
The detection object has a second insertion hole formed so that the detection object can be inserted, and is assembled to one side of the holder member so that the main driving gear and the driven gear are rotatably sandwiched between the holder member and the detection target object. A first cover member that forms a first space that accommodates the driven gear so that a part of the main driving gear faces the first space;
A magnetic detection element that detects a change in a magnetic field caused by rotation of the magnet so as to face the magnet through the opening;
A circuit board on which the magnetic detection element is mounted;
A third insertion hole is formed so that the detection object can be inserted therethrough, and is attached to the other side of the holder member to form a second space for accommodating the circuit board between the holder member and the second member. Two cover members,
The rotation angle detecting device, wherein the opening is closed by the circuit board. The rotation angle detection device according to claim 1,
The holder member, the first cover member, the main driving gear, and the driven gear are molded from a synthetic resin material, and are processed from a metal plate between the main driving gear, the driven gear, and the first cover member. A rotation angle detecting device, wherein a sheet-like member is interposed. The rotation angle detection device according to claim 1,
The rotation angle detecting device, wherein the holder member, the main driving gear and the driven gear are molded from a synthetic resin material, and at least the first cover member is processed from a metal plate.

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